Worcester, Bosch Group, Cotswold Way, Warndon, Worcester WR4 9SW.
Telephone: 01905 754624 Fax: 01905 753130.
Technical Helpline 08705 266241.
Worcester, Bosch Group is a trading name of BBT Thermotechnology UK Limited
6 720 610 414b 10/05
134
Hot Water Mode:
The appliance operates to supply only domestic hot water when
the heating temperature mode is fully anti-clockwise, at the – position
or the timer is programmed to OFF mode.
The flow is limited within the appliance to give a hot water
delivery rate to a maximum of 9.0 (±15%) litres/minute-25Si or 10.0
(±15%) litres/minute-28Si.
Hot Water and
Central Heating
mode:
When a demand is made for
heating by the system controls
(i.e. a programmer or room
thermostat).
The pump will energise
circulating primary water
around the heating system
and the burner will light. The
heat output from the
appliance in this mode has
been factory set to maximum.
The appliance will operate as
necessary to maintain the
temperature of the radiators at
the level set by the adjustment
of the Heating Temperature
Control Knob. (See Fig. 2.)
If the system no longer
requires heat to maintain the
desired room temperature, the
burner will extinguish. The
pump will continue to run for
a short period to dissipate the
residual heat from the
appliance and then switch off.
The appliance will supply
heat to the central heating
system as required. A demand
for hot water at a tap or
shower will override the
central heating function for
the period of the domestic hot
water demand.
GUARANTEE
REGISTRATION
You should complete and return the postpaid Guarantee
Registration Card within 30 days of purchase.
The card will register you as the owner of your new
Worcester Si II appliance and, while this will not affect your
statutory rights in any way, it will assist us to maintain an
effective and efficient customer service by establishing a
reference and permanent record for your boiler.
IMPORTANT: SERIAL NUMBER. Copy the number off the
Guarantee Card.
FOR YOUR OWN RECORD
MODEL
SERIAL NUMBER
TYPE/SIZE DATE OF INSTALLATION
MAINTAINING YOUR
APPLIANCE
Your new Worcester Si gas-fired appliance represents a long-
term investment in a reliable, high quality product.
In order to realise its maximum working life, and to ensure
it continues to operate at peak efficiency and performance, it is
essential that your boiler receives regular, competent servicing
and annual maintenance checks beyond the initial 24 month
guarantee period*.
Regular service contracts can be arranged with your installer
– however if you have difficulty making a satisfactory
arrangement simply contact Worcester on
08457 256206 for help.
If you would like to know more about Worcester’s extended
warranty options please tick the appropriate box on your
warranty registration card.
*subject to terms and conditions on page 15.
Fig. 1. System Diagram.
Automatic air
vent
Primary heat
exchanger
Circulating
pump
Fixed
by-pass
Relief valve
CH
flow
Domestic
hot water
flow
Domestic
cold
supply
CH
return
Relief valve
discharge
Domestic
water flow
turbine
Expansion
vessel
24-28Si
II
SERIES
USER INSTRUCTIONS &
CUSTOMER CARE GUIDE
G.C. NUMBERS
APPLIANCE NATURAL GAS L.P.G.
24Si II 47 311 65 47 311 66
28Si II 47 311 67 47 311 68
www.worcester-bosch.co.uk
Worcester supports the
Benchmark code of practice
CORGI CONTACT
All CORGI Registered installers carry a CORGI ID card and
have a registration number. Both should be recorded in your
central heating log book
. You can check your installer is
CORGI Registered by calling CORGI on 01256 372300
Vote for your
‘Installer of the year’ at
www.worcester-bosch.co.uk
CONTACT NUMBERS:
UK Contact Centre Tel. 08457 256 206
UK Contact Centre Fax. 01905 757536
Scotland only Fax. 01506 441 687
Eire Tel: 01 494 0099
OPERATING HOURS:
Mon - Fri 7.00am to 8.00pm
Sat 8.00am to 5.00pm
Sun 9.00am to 12.00pm
Please contact our UK Contact Centre number where our friendly
operators will book your call with one of our team of nationwide
engineers.
NOTE:
Please refer to our website for our bank holiday opening hours.
www.worcester-bosch.co.uk
15
EXCELLENCE COMES
AS STANDARD
Thank you for purchasing a Worcester SiII Series gas-fired
combination appliance.
The SiII Series appliances are made by Worcester and the
strictest quality control standards are demanded throughout
every stage of production.
Indeed, Worcester, part of the Bosch Group have led the
field in innovative
appliance design and
performance for more
than 40 years.
The result is that your
new Worcester SiII
appliance offers you the
very best of everything -
quality, efficiency,
economical running costs,
proven reliability and
value for money.
What’s more, you also have the assurance of our no-
nonsense 1 year parts and labour guarantee.
Page No.
Operating Instructions
.................................... 3-11
Fault and Breakdowns 12
Maintenance and
Extended Warranty
Information ............ 13-14
Guarantee Details ... 15-16
CONTENTS
2
14
YOUR WORCESTER
Si II SERIES
GUARANTEE
This appliance is guaranteed from the date of installation
subject to the following conditions & exceptions.
1. The appliance is guaranteed for a
period of 24 calendar months
subject to the return of the
guarantee card within 30 days of
installation and the first 12 months
service and inspection having been
carried out to the satisfaction of BBT
Thermotechnology UK Ltd. Please
note that this service is not covered
under the terms & conditions of the
warranty and would therefore incur
a charge.
2. That during the period of this
guarantee any components of the
unit which are Proved to be faulty
or defective in manufacture will be
exchanged or repaired Free of
material charges and free of labour
charges if repaired directly by BBT
Thermotechnology UK Ltd. Invoices
for attendance and repair of this
appliance by third parties will not
be accepted for payment by BBT.
3. That the householder may be asked
to prove the date of installation and
that the appliance was correctly
commissioned. This information
must then be documented in the
Benchmark Gas Boiler
Commissioning Checklist.
4. That any product or part thereof
returned for servicing under the
guarantee must be accompanied by
a claim stating the model, serial
number and date of installation.
5. That BBT Thermotechnology UK Ltd
will not accept responsibility for
damage caused by faulty
installation, neglect, misuse,
accidental damage or the non-
observance of the instructions
contained in the Installation and
Users instructions leaflets.
6. That the appliance has been used
only for normal domestic purposes,
for which it was designed.
7. That this guarantee applies only to
equipment purchased and used in
mainland Great Britain.
This guarantee is given in addition to all your normal statutory rights.
Worcester, Bosch Group is a trading name of BBT Thermotechnology UK Ltd.
GENERAL
INFORMATION
GAS SAFETY (INSTALLATION AND USE)
REGULATIONS
It is the law, in GB, that all gas appliances must be installed by a
competent person in accordance with the above regulations. Failure to
install appliances correctly could lead to prosecution. It is in your
interest and that of safety to ensure compliance with the law. The
manufacturer’s notes must not be taken, in any way, as over-riding
statutory obligations.
In GB, a competent person is someone registered with CORGI. All
CORGI registered installers carry a CORGI ID card and have a
registration number. Both should be recorded in the BENCHMARK
checklist. You can check that your installer is CORGI registered by
calling CORGI on 01256 372300.
WARNING: This appliance must be earthed and protected by a 3
amp fuse to BS 1362.
ELECTRICITY SUPPLY: 230V ~ 50Hz
IMPORTANT: To get the best from your Worcester Si II appliance
please read these instructions carefully.
NOTE: In the event of a fault the appliance should not be used
until the fault has been corrected by a competent person.
BENCHMARK
The Benchmark initiative is a code of practice to encourage the
correct installation, commissioning and servicing of domestic central
heating boilers and system equipment.
A checklist can be found in the back of every installation
manual. This is a vital document that needs to be completed by the
installer at the time of installation. It confirms that the boiler has
been installed and commissioned according to the manufacturers
instructions.
In Eire the declaration found in IS 813 must be completed.
Without completion of the checklist and/or declaration,
manufacturers may refuse to respond to a call-out request. It is
important that the checklist and/or declaration are fully completed by
your installer.
GENERAL DESCRIPTION
(See Fig.1.)
The WORCESTER Si II MODELS are combined domestic hot
water and central heating appliances. They consist of a gas fired boiler
having a varying output of between 6.9kW and 24kW (24Si II) or 8.1
and 28kW (28Si II), and all the necessary controls to provide mains fed
domestic hot water and central heating.
The appliances are fitted with a manual ON/OFF Switch.
The appliances can operate in one of two modes. Hot water only
or hot water and central heating.
3
CONTACT CENTRES
CONTACT NUMBERS:
UK Contact Centre Tel. 08457 256 206
UK Contact Centre Fax. 01905 757536
Scotland only Fax. 01506 441 687
Eire Tel: 01 494 0099
OPERATING HOURS:
Mon - Fri 7.00am to 8.00pm
Sat 8.00am to 5.00pm
Sun 9.00am to 12.00pm
Please contact our UK Contact Centre number where our friendly
operators will book your call with one of our team of nationwide
engineers.
NOTE:
Please refer to our website for our bank holiday opening hours.
www.worcester-bosch.co.uk
15
EXCELLENCE COMES
AS STANDARD
Thank you for purchasing a Worcester SiII Series gas-fired
combination appliance.
The SiII Series appliances are made by Worcester and the
strictest quality control standards are demanded throughout
every stage of production.
Indeed, Worcester, part of the Bosch Group have led the
field in innovative
appliance design and
performance for more
than 40 years.
The result is that your
new Worcester SiII
appliance offers you the
very best of everything -
quality, efficiency,
economical running costs,
proven reliability and
value for money.
What’s more, you also have the assurance of our no-
nonsense 1 year parts and labour guarantee.
Page No.
Operating Instructions
.................................... 3-11
Fault and Breakdowns 12
Maintenance and
Extended Warranty
Information ............ 13-14
Guarantee Details ... 15-16
CONTENTS
2
14
YOUR WORCESTER
Si II SERIES
GUARANTEE
This appliance is guaranteed from the date of installation
subject to the following conditions & exceptions.
1. The appliance is guaranteed for a
period of 24 calendar months
subject to the return of the
guarantee card within 30 days of
installation and the first 12 months
service and inspection having been
carried out to the satisfaction of BBT
Thermotechnology UK Ltd. Please
note that this service is not covered
under the terms & conditions of the
warranty and would therefore incur
a charge.
2. That during the period of this
guarantee any components of the
unit which are Proved to be faulty
or defective in manufacture will be
exchanged or repaired Free of
material charges and free of labour
charges if repaired directly by BBT
Thermotechnology UK Ltd. Invoices
for attendance and repair of this
appliance by third parties will not
be accepted for payment by BBT.
3. That the householder may be asked
to prove the date of installation and
that the appliance was correctly
commissioned. This information
must then be documented in the
Benchmark Gas Boiler
Commissioning Checklist.
4. That any product or part thereof
returned for servicing under the
guarantee must be accompanied by
a claim stating the model, serial
number and date of installation.
5. That BBT Thermotechnology UK Ltd
will not accept responsibility for
damage caused by faulty
installation, neglect, misuse,
accidental damage or the non-
observance of the instructions
contained in the Installation and
Users instructions leaflets.
6. That the appliance has been used
only for normal domestic purposes,
for which it was designed.
7. That this guarantee applies only to
equipment purchased and used in
mainland Great Britain.
This guarantee is given in addition to all your normal statutory rights.
Worcester, Bosch Group is a trading name of BBT Thermotechnology UK Ltd.
GENERAL
INFORMATION
GAS SAFETY (INSTALLATION AND USE)
REGULATIONS
It is the law, in GB, that all gas appliances must be installed by a
competent person in accordance with the above regulations. Failure to
install appliances correctly could lead to prosecution. It is in your
interest and that of safety to ensure compliance with the law. The
manufacturer’s notes must not be taken, in any way, as over-riding
statutory obligations.
In GB, a competent person is someone registered with CORGI. All
CORGI registered installers carry a CORGI ID card and have a
registration number. Both should be recorded in the BENCHMARK
checklist. You can check that your installer is CORGI registered by
calling CORGI on 01256 372300.
WARNING: This appliance must be earthed and protected by a 3
amp fuse to BS 1362.
ELECTRICITY SUPPLY: 230V ~ 50Hz
IMPORTANT: To get the best from your Worcester Si II appliance
please read these instructions carefully.
NOTE: In the event of a fault the appliance should not be used
until the fault has been corrected by a competent person.
BENCHMARK
The Benchmark initiative is a code of practice to encourage the
correct installation, commissioning and servicing of domestic central
heating boilers and system equipment.
A checklist can be found in the back of every installation
manual. This is a vital document that needs to be completed by the
installer at the time of installation. It confirms that the boiler has
been installed and commissioned according to the manufacturers
instructions.
In Eire the declaration found in IS 813 must be completed.
Without completion of the checklist and/or declaration,
manufacturers may refuse to respond to a call-out request. It is
important that the checklist and/or declaration are fully completed by
your installer.
GENERAL DESCRIPTION
(See Fig.1.)
The WORCESTER Si II MODELS are combined domestic hot
water and central heating appliances. They consist of a gas fired boiler
having a varying output of between 6.9kW and 24kW (24Si II) or 8.1
and 28kW (28Si II), and all the necessary controls to provide mains fed
domestic hot water and central heating.
The appliances are fitted with a manual ON/OFF Switch.
The appliances can operate in one of two modes. Hot water only
or hot water and central heating.
3
CONTACT CENTRES
Worcester, Bosch Group, Cotswold Way, Warndon, Worcester WR4 9SW.
Telephone: 01905 754624 Fax: 01905 753130.
Technical Helpline 08705 266241.
Worcester, Bosch Group is a trading name of BBT Thermotechnology UK Limited
6 720 610 414b 10/05
134
Hot Water Mode:
The appliance operates to supply only domestic hot water when
the heating temperature mode is fully anti-clockwise, at the – position
or the timer is programmed to OFF mode.
The flow is limited within the appliance to give a hot water
delivery rate to a maximum of 9.0 (±15%) litres/minute-25Si or 10.0
(±15%) litres/minute-28Si.
Hot Water and
Central Heating
mode:
When a demand is made for
heating by the system controls
(i.e. a programmer or room
thermostat).
The pump will energise
circulating primary water
around the heating system
and the burner will light. The
heat output from the
appliance in this mode has
been factory set to maximum.
The appliance will operate as
necessary to maintain the
temperature of the radiators at
the level set by the adjustment
of the Heating Temperature
Control Knob. (See Fig. 2.)
If the system no longer
requires heat to maintain the
desired room temperature, the
burner will extinguish. The
pump will continue to run for
a short period to dissipate the
residual heat from the
appliance and then switch off.
The appliance will supply
heat to the central heating
system as required. A demand
for hot water at a tap or
shower will override the
central heating function for
the period of the domestic hot
water demand.
GUARANTEE
REGISTRATION
You should complete and return the postpaid Guarantee
Registration Card within 30 days of purchase.
The card will register you as the owner of your new
Worcester Si II appliance and, while this will not affect your
statutory rights in any way, it will assist us to maintain an
effective and efficient customer service by establishing a
reference and permanent record for your boiler.
IMPORTANT: SERIAL NUMBER. Copy the number off the
Guarantee Card.
FOR YOUR OWN RECORD
MODEL
SERIAL NUMBER
TYPE/SIZE DATE OF INSTALLATION
MAINTAINING YOUR
APPLIANCE
Your new Worcester Si gas-fired appliance represents a long-
term investment in a reliable, high quality product.
In order to realise its maximum working life, and to ensure
it continues to operate at peak efficiency and performance, it is
essential that your boiler receives regular, competent servicing
and annual maintenance checks beyond the initial 24 month
guarantee period*.
Regular service contracts can be arranged with your installer
– however if you have difficulty making a satisfactory
arrangement simply contact Worcester on
08457 256206 for help.
If you would like to know more about Worcester’s extended
warranty options please tick the appropriate box on your
warranty registration card.
*subject to terms and conditions on page 15.
Fig. 1. System Diagram.
Automatic air
vent
Primary heat
exchanger
Circulating
pump
Fixed
by-pass
Relief valve
CH
flow
Domestic
hot water
flow
Domestic
cold
supply
CH
return
Relief valve
discharge
Domestic
water flow
turbine
Expansion
vessel
24-28Si
II
SERIES
USER INSTRUCTIONS &
CUSTOMER CARE GUIDE
G.C. NUMBERS
APPLIANCE NATURAL GAS L.P.G.
24Si II 47 311 65 47 311 66
28Si II 47 311 67 47 311 68
www.worcester-bosch.co.uk
Worcester supports the
Benchmark code of practice
CORGI CONTACT
All CORGI Registered installers carry a CORGI ID card and
have a registration number. Both should be recorded in your
central heating log book
. You can check your installer is
CORGI Registered by calling CORGI on 01256 372300
Vote for your
‘Installer of the year’ at
www.worcester-bosch.co.uk
12 5
CENTRAL HEATING SYSTEM
During the first few hours of operation of the central heating
system, check that all radiators are being heated at an even rate.
Should the upper area of a radiator be at a lower temperature than the
base of the radiator, it should be vented by releasing air through the
venting screw at the top of each radiator. Make sure your installer
shows you how to carry out the operation. Repeated venting will
reduce the quantity of water in the system and this must be
replenished for safe and satisfactory operation of the appliance.
Should water leaks be found in the system or excessive venting be
required from any radiator, a service engineer should be contacted and
the system corrected.
GENERAL NOTES
9
INDICATOR LIGHTS
Flame detection indicator:
OFF: Burner off
ON: Burner on
8
OPERATION OF
CONTROLS
More than 30% of all calls made to our contact centre reporting
appliance faults or breakdowns prove to be false alarms, as there is often
a simple explanation for the apparent malfunction.
So, to help you save time and money – not to mention frustration
and inconvenience – please refer to the General Information, Notes and
Lighting Instructions ensuring all controls are set correctly.
If, after following the instructions the appliance still fails to operate
correctly call the Worcester Contact Centre. Arrangements will be made
for an engineer to call as soon as possible.
CALL-OUT CHARGES
All of our field service engineers are factory trained.
If you request a visit from an engineer and your appliance has been
installed within the last 12 months, no charge will be made for parts
and/or labour, providing:
•
The appliance was commissioned correctly on installation.
•
An appliance fault is found and the appliance has been installed
within the past 12 months.
A call-out charge will be made where:
•
The appliance has been installed for over 12 months, or
•
Our Field Service Engineer finds no fault with the appliance (see
note), or
•
The cause of breakdown is with other parts of your
plumbing/heating system, or with equipment not supplied by Worcester.
NOTE: Invoices for attendance and/or repair work carried out on
your appliance by any third party will not be accepted.
APPLIANCE FAILS TO
OPERATE
Fig. 2. Controls.
The appliance is fitted with the following controls:
OPERATING SWITCH
In the ‘0’ position there is no mains electricity to the control
board.
In the ‘I’ position mains electricity is connected to the control
board.
CENTRAL HEATING TEMPERATURE
CONTROL
The position of this knob will determine the temperature of the
water delivered to the radiators between fully clockwise and anti-
clockwise to the mark. When the knob is turned anti-clockwise
past the position towards the ‘’(Summer Position), then the
appliance will operate in the HOT WATER mode only and no heat will
be delivered to the radiators.
DOMESTIC HOT WATER TEMPERATURE
CONTROL
The position of this knob will determine the temperature of the
water delivered at the domestic hot water taps between fully
clockwise and anti- clockwise positions.
By slightly reducing the flow of domestic water from the tap, the
delivery temperature of the water will be further increased. This is of
particular advantage in the winter, for example to increase bath water
temperature and to remove heavy grease deposits on plates, etc. Also
this will provide an added advantage of reducing the delay before hot
water is obtained.
FACIA MOUNTED PROGRAMMER (if fitted)
Your installer may have mounted either a mechanical or an
electronic programmer into the facia of your appliance. Operating
instructions are supplied with the programmer.
RESET BUTTON
Press this button in for five seconds if the indicator light is
flashing slowly.
If indicator lamp is flashing fast turn power OFF and ON at the
boiler to reset.
SYSTEM PRESSURE GAUGE
The black needle will show the actual pressure in the system.
When operating the pressure indicated must not be greater than
2.5bar. If it is then contact your installer.
Mains electricity
On/Off
Fault indicator and
reset button
Flame detection
indicator
CH temp
control knob
DHW temp
control knob
System pressure
gauge
▲
The appliance must be fitted to a sealed heating system which is
pre-pressurised. Your installer will advise you on the minimum and
maximum pressure that should be indicated on the pressure gauge.
See Fig. 2. Check regularly that this pressure is maintained and
contact your installer or maintenance engineer if there is a permanent
significant drop in pressure indicated on the gauge. If the system loses
pressure it should be re-pressurised as instructed by the installer (N.B.
Maximum operating pressure 2.5 bar).
SEALED HEATING SYSTEM
!
▲
Fault indicator:
FLASHING SLOW: Ignition lockout or
(once per second) boiler overheat
FLASHING FAST: Appliance fault
(five times a second)
11
6
Your installer will
have provided adequate
space around the
appliance for safety and
servicing. Do not restrict
this space by the
addition of cupboards,
shelves etc. close to the
appliance.
NOTE: If the appliance is to be enclosed after the
installation then the instructions given in Section 6, Air
Supply, of the Installation Book MUST be followed.
ROOM THERMOSTAT
A room thermostat must be fitted for control of the central
heating temperature. It will be located in one room of the home. The
method of setting a room thermostat varies with the type and
manufacture. Refer to the instructions supplied with the room
thermostat.
THERMOSTATIC RADIATOR VALVES
If thermostatic radiator valves are fitted to the system then they
must conform to the requirements of BS2767. The radiator located in
the room where the room thermostat is sited must be controlled by a
thermostatic radiator valve.
SHOWERS, BIDETS, TAPS AND MIXING
VALVES
Standard hot and cold taps and mixing valves used with the
appliance must be suitable for operating at mains pressure.
Thermostatically controlled shower valves will guard against the flow
of water at too high a temperature.
If using a pressure equalising valve, set the Domestic Hot Water
temperature control knob to the ‘MAX’ position.
Hot and cold mains fed water can be supplied direct to an
overrim flushing bidet subject to local water company requirements.
With all mains fed systems the flow of water from the individual
taps will vary with the number of outlets operated simultaneously
and the cold water mains supply pressure to the property. Flow
balancing using ‘Ball-o-Fix’ type valves is recommended to avoid an
excessive reduction in flow to individual outlets.
For further information contact The Worcester Technical
Helpline.
HOT AND COLD FLOW
If the flow of water demanded from both hot and cold service
outlets is dependent upon mains supply, it may not be possible in
some installations to operate all outlets simultaneously.
WATER MAINS FAILURE
It is important to note that in the event of a mains water supply
failure, no tap water will be available until the mains supply is
restored. The appliance can still be used for heating provided that the
system is of the sealed system type.
10
TO LIGHT THE APPLIANCE
Check that the water valves to the central heating circuit are open.
Check that the black needle on the pressure gauge is not below
the required pressure.
Switch on the mains electricity. Set the room thermostat to
maximum. Turn the central heating temperature control knob fully
clockwise.
The burner will light and the red flame detection indicator will light.
Set the central heating and hot water temperature control knobs
and the room thermostat, if fitted, to the desired temperature.
TO STOP THE APPLIANCE
For Short Periods
Turn the central heating temperature control knob fully anti-
clockwise to the ‘O’ position.
For Long Periods
Turn the operating switch to the ‘O’ position. Switch off the
mains electricity.
A facia mounted electronic programmer will retain its settings for
about two weeks, after which it will return to the factory set
programme. The time will be saved for approximately 7 hours. The
display will disappear after approximately 1 hour.
A facia mounted mechanical programmer will require resetting
once the operating switch has been set to ‘O’, or the mains supply has
been disconnected.
ELECTRICITY SUPPLY
FAILURE
If the electricity supply fails the appliance will not operate. Once
the supply is restored the appliance will return to normal operation. If
a programmer is fitted, check that the settings have been maintained.
OVERHEAT CUT-OFF
THERMOSTAT
The appliance will enter a lockout condition in the event of
overheating.
An overheat cut-off thermostat is fitted to the appliance which
will interrupt the electricity supply to the gas valve.
If the overheat cut-off has operated, the fault indicator will flash
once a second. If this condition continues to occur, then call a service
engineer.
The appliance can be reset by pressing the fault indicator button
and holding in for 5 seconds when the appliance has cooled.
7
USE IN HARD WATER AREAS
Normally there is no need for scale protection. However, in areas
of exceptionally hard water supply it is recommended that an In-Line
scale inhibitor be fitted.
Installation should be strictly in accordance with the
requirements of the local Water Company. An isolating valve to
facilitate servicing should be incorporated.
The water hardness may be determined using the standard test
paper or by reference to the local Water Company.
Further information may be obtained from The Worcester
Technical Helpline.
VENTILATION OF ROOM SEALED FANNED
FLUE (RSF) APPLIANCES
These are room sealed appliances and any ventilation openings
in a wall or door must not be obstructed. Do not allow the flue
terminal fitted on the outside wall to become obstructed or damaged.
NOTE: Do not place anything on top of the appliance.
If the appliance is fitted in a compartment do not use the
compartment for storage purposes unless it conforms to the
requirements of BS 6798:1987: Section 6. It is essential that the airing
space is separated from the boiler space by a perforated non-
combustible partition as described in BS 6798:1987.
CIRCULATING PUMP
This may be fitted with a speed adjuster. If so it will be factory
set at maximum and should not be changed.
FROST PRECAUTIONS
If the appliance is not to be used for a long period of time and
there is a likelihood of freezing, then the appliance should be drained.
The Worcester Technical Helpline will advise you on suitable frost
precautions. For short periods the built-in frost protection of the
appliance will be adequate.
SERVICE
Annual servicing is important in order to ensure continuing high
efficiency and long life for your appliance. In the event of any
difficulty in making suitable servicing arrangements, Worcester
personnel or other competent persons will discuss regular servicing
arrangements and offer a comprehensive maintenance contract.
WARNING
If a gas leak exists, or is suspected, turn off the gas supply to the
appliance at the service cock and consult your local service engineer.
Do not touch any electrical switches to turn them either on or off.
Open all windows and doors. Do not smoke. Extinguish all naked lights.
CLEANING
Do not use abrasive cleaners on the outer casing. Use a damp
cloth and a little detergent.
Under no circumstances should any seal on the boiler be broken.
IGNITION LOCKOUT
The appliance will enter a lockout condition in the event of the
burner failing to ignite.
If the burner fails to light after 5 attempts the electricity supply
to the gas valve will be interrupted.
If ignition lockout has occurred, the fault indicator will flash
slowly (approximately once per second).
The appliance can be reset by pressing the reset button and
holding in for 5 seconds. Check that the gas supply has not been
interrupted.
If this condition continues to occur, then call a service engineer.
AIR FLOW DEVICE
The appliance will enter a lockout condition in the event of an
air flow fault.
If the controls fail to detect the correct air flow through the
appliance the electricity supply to the gas valve will be interrupted.
If an air flow fault has occurred, the fault indicator will flash
(approximately five times per second).
The appliance will try to re-light after a waiting period of
approximately 5 minutes Check that the flue terminal has not been
obstructed or damaged.
If this condition continues to occur, then call a service engineer.
TO LIGHT AND STOP THE
APPLIANCE
RSF
Left-hand side 10 80
Right-hand side 10 80
In Front 600 240
Above the casing 180 30
Below 200 200
CLEARANCES
Unventilated
compartment
above flue elbow
or turret
Minimum clearances in millimetres.
11
6
Your installer will
have provided adequate
space around the
appliance for safety and
servicing. Do not restrict
this space by the
addition of cupboards,
shelves etc. close to the
appliance.
NOTE: If the appliance is to be enclosed after the
installation then the instructions given in Section 6, Air
Supply, of the Installation Book MUST be followed.
ROOM THERMOSTAT
A room thermostat must be fitted for control of the central
heating temperature. It will be located in one room of the home. The
method of setting a room thermostat varies with the type and
manufacture. Refer to the instructions supplied with the room
thermostat.
THERMOSTATIC RADIATOR VALVES
If thermostatic radiator valves are fitted to the system then they
must conform to the requirements of BS2767. The radiator located in
the room where the room thermostat is sited must be controlled by a
thermostatic radiator valve.
SHOWERS, BIDETS, TAPS AND MIXING
VALVES
Standard hot and cold taps and mixing valves used with the
appliance must be suitable for operating at mains pressure.
Thermostatically controlled shower valves will guard against the flow
of water at too high a temperature.
If using a pressure equalising valve, set the Domestic Hot Water
temperature control knob to the ‘MAX’ position.
Hot and cold mains fed water can be supplied direct to an
overrim flushing bidet subject to local water company requirements.
With all mains fed systems the flow of water from the individual
taps will vary with the number of outlets operated simultaneously
and the cold water mains supply pressure to the property. Flow
balancing using ‘Ball-o-Fix’ type valves is recommended to avoid an
excessive reduction in flow to individual outlets.
For further information contact The Worcester Technical
Helpline.
HOT AND COLD FLOW
If the flow of water demanded from both hot and cold service
outlets is dependent upon mains supply, it may not be possible in
some installations to operate all outlets simultaneously.
WATER MAINS FAILURE
It is important to note that in the event of a mains water supply
failure, no tap water will be available until the mains supply is
restored. The appliance can still be used for heating provided that the
system is of the sealed system type.
10
TO LIGHT THE APPLIANCE
Check that the water valves to the central heating circuit are open.
Check that the black needle on the pressure gauge is not below
the required pressure.
Switch on the mains electricity. Set the room thermostat to
maximum. Turn the central heating temperature control knob fully
clockwise.
The burner will light and the red flame detection indicator will light.
Set the central heating and hot water temperature control knobs
and the room thermostat, if fitted, to the desired temperature.
TO STOP THE APPLIANCE
For Short Periods
Turn the central heating temperature control knob fully anti-
clockwise to the ‘O’ position.
For Long Periods
Turn the operating switch to the ‘O’ position. Switch off the
mains electricity.
A facia mounted electronic programmer will retain its settings for
about two weeks, after which it will return to the factory set
programme. The time will be saved for approximately 7 hours. The
display will disappear after approximately 1 hour.
A facia mounted mechanical programmer will require resetting
once the operating switch has been set to ‘O’, or the mains supply has
been disconnected.
ELECTRICITY SUPPLY
FAILURE
If the electricity supply fails the appliance will not operate. Once
the supply is restored the appliance will return to normal operation. If
a programmer is fitted, check that the settings have been maintained.
OVERHEAT CUT-OFF
THERMOSTAT
The appliance will enter a lockout condition in the event of
overheating.
An overheat cut-off thermostat is fitted to the appliance which
will interrupt the electricity supply to the gas valve.
If the overheat cut-off has operated, the fault indicator will flash
once a second. If this condition continues to occur, then call a service
engineer.
The appliance can be reset by pressing the fault indicator button
and holding in for 5 seconds when the appliance has cooled.
7
USE IN HARD WATER AREAS
Normally there is no need for scale protection. However, in areas
of exceptionally hard water supply it is recommended that an In-Line
scale inhibitor be fitted.
Installation should be strictly in accordance with the
requirements of the local Water Company. An isolating valve to
facilitate servicing should be incorporated.
The water hardness may be determined using the standard test
paper or by reference to the local Water Company.
Further information may be obtained from The Worcester
Technical Helpline.
VENTILATION OF ROOM SEALED FANNED
FLUE (RSF) APPLIANCES
These are room sealed appliances and any ventilation openings
in a wall or door must not be obstructed. Do not allow the flue
terminal fitted on the outside wall to become obstructed or damaged.
NOTE: Do not place anything on top of the appliance.
If the appliance is fitted in a compartment do not use the
compartment for storage purposes unless it conforms to the
requirements of BS 6798:1987: Section 6. It is essential that the airing
space is separated from the boiler space by a perforated non-
combustible partition as described in BS 6798:1987.
CIRCULATING PUMP
This may be fitted with a speed adjuster. If so it will be factory
set at maximum and should not be changed.
FROST PRECAUTIONS
If the appliance is not to be used for a long period of time and
there is a likelihood of freezing, then the appliance should be drained.
The Worcester Technical Helpline will advise you on suitable frost
precautions. For short periods the built-in frost protection of the
appliance will be adequate.
SERVICE
Annual servicing is important in order to ensure continuing high
efficiency and long life for your appliance. In the event of any
difficulty in making suitable servicing arrangements, Worcester
personnel or other competent persons will discuss regular servicing
arrangements and offer a comprehensive maintenance contract.
WARNING
If a gas leak exists, or is suspected, turn off the gas supply to the
appliance at the service cock and consult your local service engineer.
Do not touch any electrical switches to turn them either on or off.
Open all windows and doors. Do not smoke. Extinguish all naked lights.
CLEANING
Do not use abrasive cleaners on the outer casing. Use a damp
cloth and a little detergent.
Under no circumstances should any seal on the boiler be broken.
IGNITION LOCKOUT
The appliance will enter a lockout condition in the event of the
burner failing to ignite.
If the burner fails to light after 5 attempts the electricity supply
to the gas valve will be interrupted.
If ignition lockout has occurred, the fault indicator will flash
slowly (approximately once per second).
The appliance can be reset by pressing the reset button and
holding in for 5 seconds. Check that the gas supply has not been
interrupted.
If this condition continues to occur, then call a service engineer.
AIR FLOW DEVICE
The appliance will enter a lockout condition in the event of an
air flow fault.
If the controls fail to detect the correct air flow through the
appliance the electricity supply to the gas valve will be interrupted.
If an air flow fault has occurred, the fault indicator will flash
(approximately five times per second).
The appliance will try to re-light after a waiting period of
approximately 5 minutes Check that the flue terminal has not been
obstructed or damaged.
If this condition continues to occur, then call a service engineer.
TO LIGHT AND STOP THE
APPLIANCE
RSF
Left-hand side 10 80
Right-hand side 10 80
In Front 600 240
Above the casing 180 30
Below 200 200
CLEARANCES
Unventilated
compartment
above flue elbow
or turret
Minimum clearances in millimetres.
12 5
CENTRAL HEATING SYSTEM
During the first few hours of operation of the central heating
system, check that all radiators are being heated at an even rate.
Should the upper area of a radiator be at a lower temperature than the
base of the radiator, it should be vented by releasing air through the
venting screw at the top of each radiator. Make sure your installer
shows you how to carry out the operation. Repeated venting will
reduce the quantity of water in the system and this must be
replenished for safe and satisfactory operation of the appliance.
Should water leaks be found in the system or excessive venting be
required from any radiator, a service engineer should be contacted and
the system corrected.
GENERAL NOTES
9
INDICATOR LIGHTS
Flame detection indicator:
OFF: Burner off
ON: Burner on
8
OPERATION OF
CONTROLS
More than 30% of all calls made to our contact centre reporting
appliance faults or breakdowns prove to be false alarms, as there is often
a simple explanation for the apparent malfunction.
So, to help you save time and money – not to mention frustration
and inconvenience – please refer to the General Information, Notes and
Lighting Instructions ensuring all controls are set correctly.
If, after following the instructions the appliance still fails to operate
correctly call the Worcester Contact Centre. Arrangements will be made
for an engineer to call as soon as possible.
CALL-OUT CHARGES
All of our field service engineers are factory trained.
If you request a visit from an engineer and your appliance has been
installed within the last 12 months, no charge will be made for parts
and/or labour, providing:
•
The appliance was commissioned correctly on installation.
•
An appliance fault is found and the appliance has been installed
within the past 12 months.
A call-out charge will be made where:
•
The appliance has been installed for over 12 months, or
•
Our Field Service Engineer finds no fault with the appliance (see
note), or
•
The cause of breakdown is with other parts of your
plumbing/heating system, or with equipment not supplied by Worcester.
NOTE: Invoices for attendance and/or repair work carried out on
your appliance by any third party will not be accepted.
APPLIANCE FAILS TO
OPERATE
Fig. 2. Controls.
The appliance is fitted with the following controls:
OPERATING SWITCH
In the ‘0’ position there is no mains electricity to the control
board.
In the ‘I’ position mains electricity is connected to the control
board.
CENTRAL HEATING TEMPERATURE
CONTROL
The position of this knob will determine the temperature of the
water delivered to the radiators between fully clockwise and anti-
clockwise to the mark. When the knob is turned anti-clockwise
past the position towards the ‘’(Summer Position), then the
appliance will operate in the HOT WATER mode only and no heat will
be delivered to the radiators.
DOMESTIC HOT WATER TEMPERATURE
CONTROL
The position of this knob will determine the temperature of the
water delivered at the domestic hot water taps between fully
clockwise and anti- clockwise positions.
By slightly reducing the flow of domestic water from the tap, the
delivery temperature of the water will be further increased. This is of
particular advantage in the winter, for example to increase bath water
temperature and to remove heavy grease deposits on plates, etc. Also
this will provide an added advantage of reducing the delay before hot
water is obtained.
FACIA MOUNTED PROGRAMMER (if fitted)
Your installer may have mounted either a mechanical or an
electronic programmer into the facia of your appliance. Operating
instructions are supplied with the programmer.
RESET BUTTON
Press this button in for five seconds if the indicator light is
flashing slowly.
If indicator lamp is flashing fast turn power OFF and ON at the
boiler to reset.
SYSTEM PRESSURE GAUGE
The black needle will show the actual pressure in the system.
When operating the pressure indicated must not be greater than
2.5bar. If it is then contact your installer.
Mains electricity
On/Off
Fault indicator and
reset button
Flame detection
indicator
CH temp
control knob
DHW temp
control knob
System pressure
gauge
▲
The appliance must be fitted to a sealed heating system which is
pre-pressurised. Your installer will advise you on the minimum and
maximum pressure that should be indicated on the pressure gauge.
See Fig. 2. Check regularly that this pressure is maintained and
contact your installer or maintenance engineer if there is a permanent
significant drop in pressure indicated on the gauge. If the system loses
pressure it should be re-pressurised as instructed by the installer (N.B.
Maximum operating pressure 2.5 bar).
SEALED HEATING SYSTEM
!
▲
Fault indicator:
FLASHING SLOW: Ignition lockout or
(once per second) boiler overheat
FLASHING FAST: Appliance fault
(five times a second)
12 5
CENTRAL HEATING SYSTEM
During the first few hours of operation of the central heating
system, check that all radiators are being heated at an even rate.
Should the upper area of a radiator be at a lower temperature than the
base of the radiator, it should be vented by releasing air through the
venting screw at the top of each radiator. Make sure your installer
shows you how to carry out the operation. Repeated venting will
reduce the quantity of water in the system and this must be
replenished for safe and satisfactory operation of the appliance.
Should water leaks be found in the system or excessive venting be
required from any radiator, a service engineer should be contacted and
the system corrected.
GENERAL NOTES
9
INDICATOR LIGHTS
Flame detection indicator:
OFF: Burner off
ON: Burner on
8
OPERATION OF
CONTROLS
More than 30% of all calls made to our contact centre reporting
appliance faults or breakdowns prove to be false alarms, as there is often
a simple explanation for the apparent malfunction.
So, to help you save time and money – not to mention frustration
and inconvenience – please refer to the General Information, Notes and
Lighting Instructions ensuring all controls are set correctly.
If, after following the instructions the appliance still fails to operate
correctly call the Worcester Contact Centre. Arrangements will be made
for an engineer to call as soon as possible.
CALL-OUT CHARGES
All of our field service engineers are factory trained.
If you request a visit from an engineer and your appliance has been
installed within the last 12 months, no charge will be made for parts
and/or labour, providing:
•
The appliance was commissioned correctly on installation.
•
An appliance fault is found and the appliance has been installed
within the past 12 months.
A call-out charge will be made where:
•
The appliance has been installed for over 12 months, or
•
Our Field Service Engineer finds no fault with the appliance (see
note), or
•
The cause of breakdown is with other parts of your
plumbing/heating system, or with equipment not supplied by Worcester.
NOTE: Invoices for attendance and/or repair work carried out on
your appliance by any third party will not be accepted.
APPLIANCE FAILS TO
OPERATE
Fig. 2. Controls.
The appliance is fitted with the following controls:
OPERATING SWITCH
In the ‘0’ position there is no mains electricity to the control
board.
In the ‘I’ position mains electricity is connected to the control
board.
CENTRAL HEATING TEMPERATURE
CONTROL
The position of this knob will determine the temperature of the
water delivered to the radiators between fully clockwise and anti-
clockwise to the mark. When the knob is turned anti-clockwise
past the position towards the ‘’(Summer Position), then the
appliance will operate in the HOT WATER mode only and no heat will
be delivered to the radiators.
DOMESTIC HOT WATER TEMPERATURE
CONTROL
The position of this knob will determine the temperature of the
water delivered at the domestic hot water taps between fully
clockwise and anti- clockwise positions.
By slightly reducing the flow of domestic water from the tap, the
delivery temperature of the water will be further increased. This is of
particular advantage in the winter, for example to increase bath water
temperature and to remove heavy grease deposits on plates, etc. Also
this will provide an added advantage of reducing the delay before hot
water is obtained.
FACIA MOUNTED PROGRAMMER (if fitted)
Your installer may have mounted either a mechanical or an
electronic programmer into the facia of your appliance. Operating
instructions are supplied with the programmer.
RESET BUTTON
Press this button in for five seconds if the indicator light is
flashing slowly.
If indicator lamp is flashing fast turn power OFF and ON at the
boiler to reset.
SYSTEM PRESSURE GAUGE
The black needle will show the actual pressure in the system.
When operating the pressure indicated must not be greater than
2.5bar. If it is then contact your installer.
Mains electricity
On/Off
Fault indicator and
reset button
Flame detection
indicator
CH temp
control knob
DHW temp
control knob
System pressure
gauge
▲
The appliance must be fitted to a sealed heating system which is
pre-pressurised. Your installer will advise you on the minimum and
maximum pressure that should be indicated on the pressure gauge.
See Fig. 2. Check regularly that this pressure is maintained and
contact your installer or maintenance engineer if there is a permanent
significant drop in pressure indicated on the gauge. If the system loses
pressure it should be re-pressurised as instructed by the installer (N.B.
Maximum operating pressure 2.5 bar).
SEALED HEATING SYSTEM
!
▲
Fault indicator:
FLASHING SLOW: Ignition lockout or
(once per second) boiler overheat
FLASHING FAST: Appliance fault
(five times a second)
11
6
Your installer will
have provided adequate
space around the
appliance for safety and
servicing. Do not restrict
this space by the
addition of cupboards,
shelves etc. close to the
appliance.
NOTE: If the appliance is to be enclosed after the
installation then the instructions given in Section 6, Air
Supply, of the Installation Book MUST be followed.
ROOM THERMOSTAT
A room thermostat must be fitted for control of the central
heating temperature. It will be located in one room of the home. The
method of setting a room thermostat varies with the type and
manufacture. Refer to the instructions supplied with the room
thermostat.
THERMOSTATIC RADIATOR VALVES
If thermostatic radiator valves are fitted to the system then they
must conform to the requirements of BS2767. The radiator located in
the room where the room thermostat is sited must be controlled by a
thermostatic radiator valve.
SHOWERS, BIDETS, TAPS AND MIXING
VALVES
Standard hot and cold taps and mixing valves used with the
appliance must be suitable for operating at mains pressure.
Thermostatically controlled shower valves will guard against the flow
of water at too high a temperature.
If using a pressure equalising valve, set the Domestic Hot Water
temperature control knob to the ‘MAX’ position.
Hot and cold mains fed water can be supplied direct to an
overrim flushing bidet subject to local water company requirements.
With all mains fed systems the flow of water from the individual
taps will vary with the number of outlets operated simultaneously
and the cold water mains supply pressure to the property. Flow
balancing using ‘Ball-o-Fix’ type valves is recommended to avoid an
excessive reduction in flow to individual outlets.
For further information contact The Worcester Technical
Helpline.
HOT AND COLD FLOW
If the flow of water demanded from both hot and cold service
outlets is dependent upon mains supply, it may not be possible in
some installations to operate all outlets simultaneously.
WATER MAINS FAILURE
It is important to note that in the event of a mains water supply
failure, no tap water will be available until the mains supply is
restored. The appliance can still be used for heating provided that the
system is of the sealed system type.
10
TO LIGHT THE APPLIANCE
Check that the water valves to the central heating circuit are open.
Check that the black needle on the pressure gauge is not below
the required pressure.
Switch on the mains electricity. Set the room thermostat to
maximum. Turn the central heating temperature control knob fully
clockwise.
The burner will light and the red flame detection indicator will light.
Set the central heating and hot water temperature control knobs
and the room thermostat, if fitted, to the desired temperature.
TO STOP THE APPLIANCE
For Short Periods
Turn the central heating temperature control knob fully anti-
clockwise to the ‘O’ position.
For Long Periods
Turn the operating switch to the ‘O’ position. Switch off the
mains electricity.
A facia mounted electronic programmer will retain its settings for
about two weeks, after which it will return to the factory set
programme. The time will be saved for approximately 7 hours. The
display will disappear after approximately 1 hour.
A facia mounted mechanical programmer will require resetting
once the operating switch has been set to ‘O’, or the mains supply has
been disconnected.
ELECTRICITY SUPPLY
FAILURE
If the electricity supply fails the appliance will not operate. Once
the supply is restored the appliance will return to normal operation. If
a programmer is fitted, check that the settings have been maintained.
OVERHEAT CUT-OFF
THERMOSTAT
The appliance will enter a lockout condition in the event of
overheating.
An overheat cut-off thermostat is fitted to the appliance which
will interrupt the electricity supply to the gas valve.
If the overheat cut-off has operated, the fault indicator will flash
once a second. If this condition continues to occur, then call a service
engineer.
The appliance can be reset by pressing the fault indicator button
and holding in for 5 seconds when the appliance has cooled.
7
USE IN HARD WATER AREAS
Normally there is no need for scale protection. However, in areas
of exceptionally hard water supply it is recommended that an In-Line
scale inhibitor be fitted.
Installation should be strictly in accordance with the
requirements of the local Water Company. An isolating valve to
facilitate servicing should be incorporated.
The water hardness may be determined using the standard test
paper or by reference to the local Water Company.
Further information may be obtained from The Worcester
Technical Helpline.
VENTILATION OF ROOM SEALED FANNED
FLUE (RSF) APPLIANCES
These are room sealed appliances and any ventilation openings
in a wall or door must not be obstructed. Do not allow the flue
terminal fitted on the outside wall to become obstructed or damaged.
NOTE: Do not place anything on top of the appliance.
If the appliance is fitted in a compartment do not use the
compartment for storage purposes unless it conforms to the
requirements of BS 6798:1987: Section 6. It is essential that the airing
space is separated from the boiler space by a perforated non-
combustible partition as described in BS 6798:1987.
CIRCULATING PUMP
This may be fitted with a speed adjuster. If so it will be factory
set at maximum and should not be changed.
FROST PRECAUTIONS
If the appliance is not to be used for a long period of time and
there is a likelihood of freezing, then the appliance should be drained.
The Worcester Technical Helpline will advise you on suitable frost
precautions. For short periods the built-in frost protection of the
appliance will be adequate.
SERVICE
Annual servicing is important in order to ensure continuing high
efficiency and long life for your appliance. In the event of any
difficulty in making suitable servicing arrangements, Worcester
personnel or other competent persons will discuss regular servicing
arrangements and offer a comprehensive maintenance contract.
WARNING
If a gas leak exists, or is suspected, turn off the gas supply to the
appliance at the service cock and consult your local service engineer.
Do not touch any electrical switches to turn them either on or off.
Open all windows and doors. Do not smoke. Extinguish all naked lights.
CLEANING
Do not use abrasive cleaners on the outer casing. Use a damp
cloth and a little detergent.
Under no circumstances should any seal on the boiler be broken.
IGNITION LOCKOUT
The appliance will enter a lockout condition in the event of the
burner failing to ignite.
If the burner fails to light after 5 attempts the electricity supply
to the gas valve will be interrupted.
If ignition lockout has occurred, the fault indicator will flash
slowly (approximately once per second).
The appliance can be reset by pressing the reset button and
holding in for 5 seconds. Check that the gas supply has not been
interrupted.
If this condition continues to occur, then call a service engineer.
AIR FLOW DEVICE
The appliance will enter a lockout condition in the event of an
air flow fault.
If the controls fail to detect the correct air flow through the
appliance the electricity supply to the gas valve will be interrupted.
If an air flow fault has occurred, the fault indicator will flash
(approximately five times per second).
The appliance will try to re-light after a waiting period of
approximately 5 minutes Check that the flue terminal has not been
obstructed or damaged.
If this condition continues to occur, then call a service engineer.
TO LIGHT AND STOP THE
APPLIANCE
RSF
Left-hand side 10 80
Right-hand side 10 80
In Front 600 240
Above the casing 180 30
Below 200 200
CLEARANCES
Unventilated
compartment
above flue elbow
or turret
Minimum clearances in millimetres.
11
6
Your installer will
have provided adequate
space around the
appliance for safety and
servicing. Do not restrict
this space by the
addition of cupboards,
shelves etc. close to the
appliance.
NOTE: If the appliance is to be enclosed after the
installation then the instructions given in Section 6, Air
Supply, of the Installation Book MUST be followed.
ROOM THERMOSTAT
A room thermostat must be fitted for control of the central
heating temperature. It will be located in one room of the home. The
method of setting a room thermostat varies with the type and
manufacture. Refer to the instructions supplied with the room
thermostat.
THERMOSTATIC RADIATOR VALVES
If thermostatic radiator valves are fitted to the system then they
must conform to the requirements of BS2767. The radiator located in
the room where the room thermostat is sited must be controlled by a
thermostatic radiator valve.
SHOWERS, BIDETS, TAPS AND MIXING
VALVES
Standard hot and cold taps and mixing valves used with the
appliance must be suitable for operating at mains pressure.
Thermostatically controlled shower valves will guard against the flow
of water at too high a temperature.
If using a pressure equalising valve, set the Domestic Hot Water
temperature control knob to the ‘MAX’ position.
Hot and cold mains fed water can be supplied direct to an
overrim flushing bidet subject to local water company requirements.
With all mains fed systems the flow of water from the individual
taps will vary with the number of outlets operated simultaneously
and the cold water mains supply pressure to the property. Flow
balancing using ‘Ball-o-Fix’ type valves is recommended to avoid an
excessive reduction in flow to individual outlets.
For further information contact The Worcester Technical
Helpline.
HOT AND COLD FLOW
If the flow of water demanded from both hot and cold service
outlets is dependent upon mains supply, it may not be possible in
some installations to operate all outlets simultaneously.
WATER MAINS FAILURE
It is important to note that in the event of a mains water supply
failure, no tap water will be available until the mains supply is
restored. The appliance can still be used for heating provided that the
system is of the sealed system type.
10
TO LIGHT THE APPLIANCE
Check that the water valves to the central heating circuit are open.
Check that the black needle on the pressure gauge is not below
the required pressure.
Switch on the mains electricity. Set the room thermostat to
maximum. Turn the central heating temperature control knob fully
clockwise.
The burner will light and the red flame detection indicator will light.
Set the central heating and hot water temperature control knobs
and the room thermostat, if fitted, to the desired temperature.
TO STOP THE APPLIANCE
For Short Periods
Turn the central heating temperature control knob fully anti-
clockwise to the ‘O’ position.
For Long Periods
Turn the operating switch to the ‘O’ position. Switch off the
mains electricity.
A facia mounted electronic programmer will retain its settings for
about two weeks, after which it will return to the factory set
programme. The time will be saved for approximately 7 hours. The
display will disappear after approximately 1 hour.
A facia mounted mechanical programmer will require resetting
once the operating switch has been set to ‘O’, or the mains supply has
been disconnected.
ELECTRICITY SUPPLY
FAILURE
If the electricity supply fails the appliance will not operate. Once
the supply is restored the appliance will return to normal operation. If
a programmer is fitted, check that the settings have been maintained.
OVERHEAT CUT-OFF
THERMOSTAT
The appliance will enter a lockout condition in the event of
overheating.
An overheat cut-off thermostat is fitted to the appliance which
will interrupt the electricity supply to the gas valve.
If the overheat cut-off has operated, the fault indicator will flash
once a second. If this condition continues to occur, then call a service
engineer.
The appliance can be reset by pressing the fault indicator button
and holding in for 5 seconds when the appliance has cooled.
7
USE IN HARD WATER AREAS
Normally there is no need for scale protection. However, in areas
of exceptionally hard water supply it is recommended that an In-Line
scale inhibitor be fitted.
Installation should be strictly in accordance with the
requirements of the local Water Company. An isolating valve to
facilitate servicing should be incorporated.
The water hardness may be determined using the standard test
paper or by reference to the local Water Company.
Further information may be obtained from The Worcester
Technical Helpline.
VENTILATION OF ROOM SEALED FANNED
FLUE (RSF) APPLIANCES
These are room sealed appliances and any ventilation openings
in a wall or door must not be obstructed. Do not allow the flue
terminal fitted on the outside wall to become obstructed or damaged.
NOTE: Do not place anything on top of the appliance.
If the appliance is fitted in a compartment do not use the
compartment for storage purposes unless it conforms to the
requirements of BS 6798:1987: Section 6. It is essential that the airing
space is separated from the boiler space by a perforated non-
combustible partition as described in BS 6798:1987.
CIRCULATING PUMP
This may be fitted with a speed adjuster. If so it will be factory
set at maximum and should not be changed.
FROST PRECAUTIONS
If the appliance is not to be used for a long period of time and
there is a likelihood of freezing, then the appliance should be drained.
The Worcester Technical Helpline will advise you on suitable frost
precautions. For short periods the built-in frost protection of the
appliance will be adequate.
SERVICE
Annual servicing is important in order to ensure continuing high
efficiency and long life for your appliance. In the event of any
difficulty in making suitable servicing arrangements, Worcester
personnel or other competent persons will discuss regular servicing
arrangements and offer a comprehensive maintenance contract.
WARNING
If a gas leak exists, or is suspected, turn off the gas supply to the
appliance at the service cock and consult your local service engineer.
Do not touch any electrical switches to turn them either on or off.
Open all windows and doors. Do not smoke. Extinguish all naked lights.
CLEANING
Do not use abrasive cleaners on the outer casing. Use a damp
cloth and a little detergent.
Under no circumstances should any seal on the boiler be broken.
IGNITION LOCKOUT
The appliance will enter a lockout condition in the event of the
burner failing to ignite.
If the burner fails to light after 5 attempts the electricity supply
to the gas valve will be interrupted.
If ignition lockout has occurred, the fault indicator will flash
slowly (approximately once per second).
The appliance can be reset by pressing the reset button and
holding in for 5 seconds. Check that the gas supply has not been
interrupted.
If this condition continues to occur, then call a service engineer.
AIR FLOW DEVICE
The appliance will enter a lockout condition in the event of an
air flow fault.
If the controls fail to detect the correct air flow through the
appliance the electricity supply to the gas valve will be interrupted.
If an air flow fault has occurred, the fault indicator will flash
(approximately five times per second).
The appliance will try to re-light after a waiting period of
approximately 5 minutes Check that the flue terminal has not been
obstructed or damaged.
If this condition continues to occur, then call a service engineer.
TO LIGHT AND STOP THE
APPLIANCE
RSF
Left-hand side 10 80
Right-hand side 10 80
In Front 600 240
Above the casing 180 30
Below 200 200
CLEARANCES
Unventilated
compartment
above flue elbow
or turret
Minimum clearances in millimetres.
12 5
CENTRAL HEATING SYSTEM
During the first few hours of operation of the central heating
system, check that all radiators are being heated at an even rate.
Should the upper area of a radiator be at a lower temperature than the
base of the radiator, it should be vented by releasing air through the
venting screw at the top of each radiator. Make sure your installer
shows you how to carry out the operation. Repeated venting will
reduce the quantity of water in the system and this must be
replenished for safe and satisfactory operation of the appliance.
Should water leaks be found in the system or excessive venting be
required from any radiator, a service engineer should be contacted and
the system corrected.
GENERAL NOTES
9
INDICATOR LIGHTS
Flame detection indicator:
OFF: Burner off
ON: Burner on
8
OPERATION OF
CONTROLS
More than 30% of all calls made to our contact centre reporting
appliance faults or breakdowns prove to be false alarms, as there is often
a simple explanation for the apparent malfunction.
So, to help you save time and money – not to mention frustration
and inconvenience – please refer to the General Information, Notes and
Lighting Instructions ensuring all controls are set correctly.
If, after following the instructions the appliance still fails to operate
correctly call the Worcester Contact Centre. Arrangements will be made
for an engineer to call as soon as possible.
CALL-OUT CHARGES
All of our field service engineers are factory trained.
If you request a visit from an engineer and your appliance has been
installed within the last 12 months, no charge will be made for parts
and/or labour, providing:
•
The appliance was commissioned correctly on installation.
•
An appliance fault is found and the appliance has been installed
within the past 12 months.
A call-out charge will be made where:
•
The appliance has been installed for over 12 months, or
•
Our Field Service Engineer finds no fault with the appliance (see
note), or
•
The cause of breakdown is with other parts of your
plumbing/heating system, or with equipment not supplied by Worcester.
NOTE: Invoices for attendance and/or repair work carried out on
your appliance by any third party will not be accepted.
APPLIANCE FAILS TO
OPERATE
Fig. 2. Controls.
The appliance is fitted with the following controls:
OPERATING SWITCH
In the ‘0’ position there is no mains electricity to the control
board.
In the ‘I’ position mains electricity is connected to the control
board.
CENTRAL HEATING TEMPERATURE
CONTROL
The position of this knob will determine the temperature of the
water delivered to the radiators between fully clockwise and anti-
clockwise to the mark. When the knob is turned anti-clockwise
past the position towards the ‘’(Summer Position), then the
appliance will operate in the HOT WATER mode only and no heat will
be delivered to the radiators.
DOMESTIC HOT WATER TEMPERATURE
CONTROL
The position of this knob will determine the temperature of the
water delivered at the domestic hot water taps between fully
clockwise and anti- clockwise positions.
By slightly reducing the flow of domestic water from the tap, the
delivery temperature of the water will be further increased. This is of
particular advantage in the winter, for example to increase bath water
temperature and to remove heavy grease deposits on plates, etc. Also
this will provide an added advantage of reducing the delay before hot
water is obtained.
FACIA MOUNTED PROGRAMMER (if fitted)
Your installer may have mounted either a mechanical or an
electronic programmer into the facia of your appliance. Operating
instructions are supplied with the programmer.
RESET BUTTON
Press this button in for five seconds if the indicator light is
flashing slowly.
If indicator lamp is flashing fast turn power OFF and ON at the
boiler to reset.
SYSTEM PRESSURE GAUGE
The black needle will show the actual pressure in the system.
When operating the pressure indicated must not be greater than
2.5bar. If it is then contact your installer.
Mains electricity
On/Off
Fault indicator and
reset button
Flame detection
indicator
CH temp
control knob
DHW temp
control knob
System pressure
gauge
▲
The appliance must be fitted to a sealed heating system which is
pre-pressurised. Your installer will advise you on the minimum and
maximum pressure that should be indicated on the pressure gauge.
See Fig. 2. Check regularly that this pressure is maintained and
contact your installer or maintenance engineer if there is a permanent
significant drop in pressure indicated on the gauge. If the system loses
pressure it should be re-pressurised as instructed by the installer (N.B.
Maximum operating pressure 2.5 bar).
SEALED HEATING SYSTEM
!
▲
Fault indicator:
FLASHING SLOW: Ignition lockout or
(once per second) boiler overheat
FLASHING FAST: Appliance fault
(five times a second)
Worcester, Bosch Group, Cotswold Way, Warndon, Worcester WR4 9SW.
Telephone: 01905 754624 Fax: 01905 753130.
Technical Helpline 08705 266241.
Worcester, Bosch Group is a trading name of BBT Thermotechnology UK Limited
6 720 610 414b 10/05
134
Hot Water Mode:
The appliance operates to supply only domestic hot water when
the heating temperature mode is fully anti-clockwise, at the – position
or the timer is programmed to OFF mode.
The flow is limited within the appliance to give a hot water
delivery rate to a maximum of 9.0 (±15%) litres/minute-25Si or 10.0
(±15%) litres/minute-28Si.
Hot Water and
Central Heating
mode:
When a demand is made for
heating by the system controls
(i.e. a programmer or room
thermostat).
The pump will energise
circulating primary water
around the heating system
and the burner will light. The
heat output from the
appliance in this mode has
been factory set to maximum.
The appliance will operate as
necessary to maintain the
temperature of the radiators at
the level set by the adjustment
of the Heating Temperature
Control Knob. (See Fig. 2.)
If the system no longer
requires heat to maintain the
desired room temperature, the
burner will extinguish. The
pump will continue to run for
a short period to dissipate the
residual heat from the
appliance and then switch off.
The appliance will supply
heat to the central heating
system as required. A demand
for hot water at a tap or
shower will override the
central heating function for
the period of the domestic hot
water demand.
GUARANTEE
REGISTRATION
You should complete and return the postpaid Guarantee
Registration Card within 30 days of purchase.
The card will register you as the owner of your new
Worcester Si II appliance and, while this will not affect your
statutory rights in any way, it will assist us to maintain an
effective and efficient customer service by establishing a
reference and permanent record for your boiler.
IMPORTANT: SERIAL NUMBER. Copy the number off the
Guarantee Card.
FOR YOUR OWN RECORD
MODEL
SERIAL NUMBER
TYPE/SIZE DATE OF INSTALLATION
MAINTAINING YOUR
APPLIANCE
Your new Worcester Si gas-fired appliance represents a long-
term investment in a reliable, high quality product.
In order to realise its maximum working life, and to ensure
it continues to operate at peak efficiency and performance, it is
essential that your boiler receives regular, competent servicing
and annual maintenance checks beyond the initial 24 month
guarantee period*.
Regular service contracts can be arranged with your installer
– however if you have difficulty making a satisfactory
arrangement simply contact Worcester on
08457 256206 for help.
If you would like to know more about Worcester’s extended
warranty options please tick the appropriate box on your
warranty registration card.
*subject to terms and conditions on page 15.
Fig. 1. System Diagram.
Automatic air
vent
Primary heat
exchanger
Circulating
pump
Fixed
by-pass
Relief valve
CH
flow
Domestic
hot water
flow
Domestic
cold
supply
CH
return
Relief valve
discharge
Domestic
water flow
turbine
Expansion
vessel
24-28Si
II
SERIES
USER INSTRUCTIONS &
CUSTOMER CARE GUIDE
G.C. NUMBERS
APPLIANCE NATURAL GAS L.P.G.
24Si II 47 311 65 47 311 66
28Si II 47 311 67 47 311 68
www.worcester-bosch.co.uk
Worcester supports the
Benchmark code of practice
CORGI CONTACT
All CORGI Registered installers carry a CORGI ID card and
have a registration number. Both should be recorded in your
central heating log book
. You can check your installer is
CORGI Registered by calling CORGI on 01256 372300
Vote for your
‘Installer of the year’ at
www.worcester-bosch.co.uk
CONTACT NUMBERS:
UK Contact Centre Tel. 08457 256 206
UK Contact Centre Fax. 01905 757536
Scotland only Fax. 01506 441 687
Eire Tel: 01 494 0099
OPERATING HOURS:
Mon - Fri 7.00am to 8.00pm
Sat 8.00am to 5.00pm
Sun 9.00am to 12.00pm
Please contact our UK Contact Centre number where our friendly
operators will book your call with one of our team of nationwide
engineers.
NOTE:
Please refer to our website for our bank holiday opening hours.
www.worcester-bosch.co.uk
15
EXCELLENCE COMES
AS STANDARD
Thank you for purchasing a Worcester SiII Series gas-fired
combination appliance.
The SiII Series appliances are made by Worcester and the
strictest quality control standards are demanded throughout
every stage of production.
Indeed, Worcester, part of the Bosch Group have led the
field in innovative
appliance design and
performance for more
than 40 years.
The result is that your
new Worcester SiII
appliance offers you the
very best of everything -
quality, efficiency,
economical running costs,
proven reliability and
value for money.
What’s more, you also have the assurance of our no-
nonsense 1 year parts and labour guarantee.
Page No.
Operating Instructions
.................................... 3-11
Fault and Breakdowns 12
Maintenance and
Extended Warranty
Information ............ 13-14
Guarantee Details ... 15-16
CONTENTS
2
14
YOUR WORCESTER
Si II SERIES
GUARANTEE
This appliance is guaranteed from the date of installation
subject to the following conditions & exceptions.
1. The appliance is guaranteed for a
period of 24 calendar months
subject to the return of the
guarantee card within 30 days of
installation and the first 12 months
service and inspection having been
carried out to the satisfaction of BBT
Thermotechnology UK Ltd. Please
note that this service is not covered
under the terms & conditions of the
warranty and would therefore incur
a charge.
2. That during the period of this
guarantee any components of the
unit which are Proved to be faulty
or defective in manufacture will be
exchanged or repaired Free of
material charges and free of labour
charges if repaired directly by BBT
Thermotechnology UK Ltd. Invoices
for attendance and repair of this
appliance by third parties will not
be accepted for payment by BBT.
3. That the householder may be asked
to prove the date of installation and
that the appliance was correctly
commissioned. This information
must then be documented in the
Benchmark Gas Boiler
Commissioning Checklist.
4. That any product or part thereof
returned for servicing under the
guarantee must be accompanied by
a claim stating the model, serial
number and date of installation.
5. That BBT Thermotechnology UK Ltd
will not accept responsibility for
damage caused by faulty
installation, neglect, misuse,
accidental damage or the non-
observance of the instructions
contained in the Installation and
Users instructions leaflets.
6. That the appliance has been used
only for normal domestic purposes,
for which it was designed.
7. That this guarantee applies only to
equipment purchased and used in
mainland Great Britain.
This guarantee is given in addition to all your normal statutory rights.
Worcester, Bosch Group is a trading name of BBT Thermotechnology UK Ltd.
GENERAL
INFORMATION
GAS SAFETY (INSTALLATION AND USE)
REGULATIONS
It is the law, in GB, that all gas appliances must be installed by a
competent person in accordance with the above regulations. Failure to
install appliances correctly could lead to prosecution. It is in your
interest and that of safety to ensure compliance with the law. The
manufacturer’s notes must not be taken, in any way, as over-riding
statutory obligations.
In GB, a competent person is someone registered with CORGI. All
CORGI registered installers carry a CORGI ID card and have a
registration number. Both should be recorded in the BENCHMARK
checklist. You can check that your installer is CORGI registered by
calling CORGI on 01256 372300.
WARNING: This appliance must be earthed and protected by a 3
amp fuse to BS 1362.
ELECTRICITY SUPPLY: 230V ~ 50Hz
IMPORTANT: To get the best from your Worcester Si II appliance
please read these instructions carefully.
NOTE: In the event of a fault the appliance should not be used
until the fault has been corrected by a competent person.
BENCHMARK
The Benchmark initiative is a code of practice to encourage the
correct installation, commissioning and servicing of domestic central
heating boilers and system equipment.
A checklist can be found in the back of every installation
manual. This is a vital document that needs to be completed by the
installer at the time of installation. It confirms that the boiler has
been installed and commissioned according to the manufacturers
instructions.
In Eire the declaration found in IS 813 must be completed.
Without completion of the checklist and/or declaration,
manufacturers may refuse to respond to a call-out request. It is
important that the checklist and/or declaration are fully completed by
your installer.
GENERAL DESCRIPTION
(See Fig.1.)
The WORCESTER Si II MODELS are combined domestic hot
water and central heating appliances. They consist of a gas fired boiler
having a varying output of between 6.9kW and 24kW (24Si II) or 8.1
and 28kW (28Si II), and all the necessary controls to provide mains fed
domestic hot water and central heating.
The appliances are fitted with a manual ON/OFF Switch.
The appliances can operate in one of two modes. Hot water only
or hot water and central heating.
3
CONTACT CENTRES
CONTACT NUMBERS:
UK Contact Centre Tel. 08457 256 206
UK Contact Centre Fax. 01905 757536
Scotland only Fax. 01506 441 687
Eire Tel: 01 494 0099
OPERATING HOURS:
Mon - Fri 7.00am to 8.00pm
Sat 8.00am to 5.00pm
Sun 9.00am to 12.00pm
Please contact our UK Contact Centre number where our friendly
operators will book your call with one of our team of nationwide
engineers.
NOTE:
Please refer to our website for our bank holiday opening hours.
www.worcester-bosch.co.uk
15
EXCELLENCE COMES
AS STANDARD
Thank you for purchasing a Worcester SiII Series gas-fired
combination appliance.
The SiII Series appliances are made by Worcester and the
strictest quality control standards are demanded throughout
every stage of production.
Indeed, Worcester, part of the Bosch Group have led the
field in innovative
appliance design and
performance for more
than 40 years.
The result is that your
new Worcester SiII
appliance offers you the
very best of everything -
quality, efficiency,
economical running costs,
proven reliability and
value for money.
What’s more, you also have the assurance of our no-
nonsense 1 year parts and labour guarantee.
Page No.
Operating Instructions
.................................... 3-11
Fault and Breakdowns 12
Maintenance and
Extended Warranty
Information ............ 13-14
Guarantee Details ... 15-16
CONTENTS
2
14
YOUR WORCESTER
Si II SERIES
GUARANTEE
This appliance is guaranteed from the date of installation
subject to the following conditions & exceptions.
1. The appliance is guaranteed for a
period of 24 calendar months
subject to the return of the
guarantee card within 30 days of
installation and the first 12 months
service and inspection having been
carried out to the satisfaction of BBT
Thermotechnology UK Ltd. Please
note that this service is not covered
under the terms & conditions of the
warranty and would therefore incur
a charge.
2. That during the period of this
guarantee any components of the
unit which are Proved to be faulty
or defective in manufacture will be
exchanged or repaired Free of
material charges and free of labour
charges if repaired directly by BBT
Thermotechnology UK Ltd. Invoices
for attendance and repair of this
appliance by third parties will not
be accepted for payment by BBT.
3. That the householder may be asked
to prove the date of installation and
that the appliance was correctly
commissioned. This information
must then be documented in the
Benchmark Gas Boiler
Commissioning Checklist.
4. That any product or part thereof
returned for servicing under the
guarantee must be accompanied by
a claim stating the model, serial
number and date of installation.
5. That BBT Thermotechnology UK Ltd
will not accept responsibility for
damage caused by faulty
installation, neglect, misuse,
accidental damage or the non-
observance of the instructions
contained in the Installation and
Users instructions leaflets.
6. That the appliance has been used
only for normal domestic purposes,
for which it was designed.
7. That this guarantee applies only to
equipment purchased and used in
mainland Great Britain.
This guarantee is given in addition to all your normal statutory rights.
Worcester, Bosch Group is a trading name of BBT Thermotechnology UK Ltd.
GENERAL
INFORMATION
GAS SAFETY (INSTALLATION AND USE)
REGULATIONS
It is the law, in GB, that all gas appliances must be installed by a
competent person in accordance with the above regulations. Failure to
install appliances correctly could lead to prosecution. It is in your
interest and that of safety to ensure compliance with the law. The
manufacturer’s notes must not be taken, in any way, as over-riding
statutory obligations.
In GB, a competent person is someone registered with CORGI. All
CORGI registered installers carry a CORGI ID card and have a
registration number. Both should be recorded in the BENCHMARK
checklist. You can check that your installer is CORGI registered by
calling CORGI on 01256 372300.
WARNING: This appliance must be earthed and protected by a 3
amp fuse to BS 1362.
ELECTRICITY SUPPLY: 230V ~ 50Hz
IMPORTANT: To get the best from your Worcester Si II appliance
please read these instructions carefully.
NOTE: In the event of a fault the appliance should not be used
until the fault has been corrected by a competent person.
BENCHMARK
The Benchmark initiative is a code of practice to encourage the
correct installation, commissioning and servicing of domestic central
heating boilers and system equipment.
A checklist can be found in the back of every installation
manual. This is a vital document that needs to be completed by the
installer at the time of installation. It confirms that the boiler has
been installed and commissioned according to the manufacturers
instructions.
In Eire the declaration found in IS 813 must be completed.
Without completion of the checklist and/or declaration,
manufacturers may refuse to respond to a call-out request. It is
important that the checklist and/or declaration are fully completed by
your installer.
GENERAL DESCRIPTION
(See Fig.1.)
The WORCESTER Si II MODELS are combined domestic hot
water and central heating appliances. They consist of a gas fired boiler
having a varying output of between 6.9kW and 24kW (24Si II) or 8.1
and 28kW (28Si II), and all the necessary controls to provide mains fed
domestic hot water and central heating.
The appliances are fitted with a manual ON/OFF Switch.
The appliances can operate in one of two modes. Hot water only
or hot water and central heating.
3
CONTACT CENTRES
Worcester, Bosch Group, Cotswold Way, Warndon, Worcester WR4 9SW.
Telephone: 01905 754624 Fax: 01905 753130.
Technical Helpline 08705 266241.
Worcester, Bosch Group is a trading name of BBT Thermotechnology UK Limited
6 720 610 414b 10/05
134
Hot Water Mode:
The appliance operates to supply only domestic hot water when
the heating temperature mode is fully anti-clockwise, at the – position
or the timer is programmed to OFF mode.
The flow is limited within the appliance to give a hot water
delivery rate to a maximum of 9.0 (±15%) litres/minute-25Si or 10.0
(±15%) litres/minute-28Si.
Hot Water and
Central Heating
mode:
When a demand is made for
heating by the system controls
(i.e. a programmer or room
thermostat).
The pump will energise
circulating primary water
around the heating system
and the burner will light. The
heat output from the
appliance in this mode has
been factory set to maximum.
The appliance will operate as
necessary to maintain the
temperature of the radiators at
the level set by the adjustment
of the Heating Temperature
Control Knob. (See Fig. 2.)
If the system no longer
requires heat to maintain the
desired room temperature, the
burner will extinguish. The
pump will continue to run for
a short period to dissipate the
residual heat from the
appliance and then switch off.
The appliance will supply
heat to the central heating
system as required. A demand
for hot water at a tap or
shower will override the
central heating function for
the period of the domestic hot
water demand.
GUARANTEE
REGISTRATION
You should complete and return the postpaid Guarantee
Registration Card within 30 days of purchase.
The card will register you as the owner of your new
Worcester Si II appliance and, while this will not affect your
statutory rights in any way, it will assist us to maintain an
effective and efficient customer service by establishing a
reference and permanent record for your boiler.
IMPORTANT: SERIAL NUMBER. Copy the number off the
Guarantee Card.
FOR YOUR OWN RECORD
MODEL
SERIAL NUMBER
TYPE/SIZE DATE OF INSTALLATION
MAINTAINING YOUR
APPLIANCE
Your new Worcester Si gas-fired appliance represents a long-
term investment in a reliable, high quality product.
In order to realise its maximum working life, and to ensure
it continues to operate at peak efficiency and performance, it is
essential that your boiler receives regular, competent servicing
and annual maintenance checks beyond the initial 24 month
guarantee period*.
Regular service contracts can be arranged with your installer
– however if you have difficulty making a satisfactory
arrangement simply contact Worcester on
08457 256206 for help.
If you would like to know more about Worcester’s extended
warranty options please tick the appropriate box on your
warranty registration card.
*subject to terms and conditions on page 15.
Fig. 1. System Diagram.
Automatic air
vent
Primary heat
exchanger
Circulating
pump
Fixed
by-pass
Relief valve
CH
flow
Domestic
hot water
flow
Domestic
cold
supply
CH
return
Relief valve
discharge
Domestic
water flow
turbine
Expansion
vessel
24-28Si
II
SERIES
USER INSTRUCTIONS &
CUSTOMER CARE GUIDE
G.C. NUMBERS
APPLIANCE NATURAL GAS L.P.G.
24Si II 47 311 65 47 311 66
28Si II 47 311 67 47 311 68
www.worcester-bosch.co.uk
Worcester supports the
Benchmark code of practice
CORGI CONTACT
All CORGI Registered installers carry a CORGI ID card and
have a registration number. Both should be recorded in your
central heating log book
. You can check your installer is
CORGI Registered by calling CORGI on 01256 372300
Vote for your
‘Installer of the year’ at
www.worcester-bosch.co.uk
/
